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Peering in Hong Kong - Hong Kong Internet Exchange

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Microsoft PowerPoint - HKNOG 0.1-Peering in HK [Read-Only]How Internet Operates –
in simple terms • Internet is composed of networks of ISPs and users
• User networks connect to ISPs
• Small ISPs connect to large ISPs
• ISPs (large or small) are interconnected or peered at Internet exchanges points (IXPs) or privately
• A few very large ISPs act as major transit providers (the so-called tier-1 backbones) for the whole world which rely on only peering arrangements to have full connectivity
• Other ISPs must be transit customers of those backbone ISPs directly or indirectly in order to gain full connectivity
• A network on Internet is called Autonomous System (AS) which is represented by AS Number (ASN)
– ASN is unique around the world
Transit Relationship
Transit Provider
All customer routes
Ordinary Peering Model
Transit Provider A
Routes of B and
• Interconnection among ISPs / data centres / content providers / cloud services providers which have different ASNs using BGP protocol
• For mutual benefits – For higher performance and lower cost
• Local Peering – Local-to-local traffic do NOT need to route through overseas
– Important to Internet development
• May have formal agreement / contract
Private Peering
• A form of BLPA having dedicated point-to-point connection between 2 AS’es
• Using cross-connect or local loop or IPL (or dedicated VLAN over IXP) to interconnect – Cost is usually shared between 2 peers
• May have multiple connections between 2 AS’es for resiliency
• Not quite cost effective – Spare bandwidth cannot be used
• Not very scalable – nC2 physical connections for n AS’es to peer fully
Internet eXchange Point • For multiple AS’es to do peering easily over a well-managed
dedicated network infrastructure
• Layer 2 infrastructure in most of the cases: – Switched Ethernet
– Co-location of Routers? • Not necessarily the case now because of advancement of Ethernet
– Only routers are allowed to connect to the switching fabric directly
– Support BLPA
– Most IXPs facilitate MLPA
• Having multiple sites within one metro area (extended layer 2) is common
• Often considered as Critical Internet Infrastructure locally, regionally or globally
IXPs in HK
– They may or may not serve you
Layer 2 IXP
BLPA over Layer 2 IXP
• Can set up BLPA with multiple peers using BGP over the same layer 2 connection
• Convenient and cost effective
• GE connection probably is the minimum for IXP connection – 10GE connection is getting more and more popular
– Link Aggregation (LACP) can be used for incremental upgrade • Best to have 2, 4 or 8 links for more balanced traffic volume
– 40GE/100GE support is coming
• The only disadvantage properly is you do not know whether your peers have congestion problem at their IXP connections
• And of course, you need to pay the IXP port charge
– Just one BGP session
• Can be provided over layer 2 IXP
– BLPA is supported at the same time
MLPA at Layer 2 IXP
Routes of ISP A Routes of All
• You have less control of your routing under MLPA
– Because MLPA route servers select the best routes for you
• With BLPA, you should have better routes and connectivity
– Possibly one AS hop less than MLPA
– May get more routes from your BLPA peers than MLPA
– Have direct control
• Do NOT blindly prefer all routes learn from MLPA route servers using higher LocalPref
– Doing BLPA more in addition to MLPA over your IXP
connection is highly recommended
• Set up a record of your ASN on and tell everyone where you are (at which IXPs and/or data centres) and that you are willing to do BLPA
• Also use it to find your potential BLPA peers
• Most content providers are willing to do bilateral peering
• Do set up BLPA with root / TLD DNS servers on IXPs to enjoy faster DNS queries
HK is an Internet hub
• A lot of overseas AS’es from all over the world have presence in HK
• They may be willing to set up direct peering with anyone for mutual benefit
– After all, they pay for the circuits to come to HK so they want higher ROI
• A lot of intra-Asia traffic is being exchanged in HK now
• HK is indeed a telecom / Internet hub
ASN & IP Addresses for Peering
– For BGP connections, must be unique
– Get one from APNIC for each of your networks which has different routing
policy / arrangement
– If you get one from your upstream, you may have it transferred to you later
• IP Addresses
– Do NOT use those assigned to you by your upstream which are NOT
supposed to be portable
– IPv4
• Get your last /22 block (probably + another /22 block later) with demonstrated need
• If you still do NOT have enough, you may need to buy from others
– IPv6:
• Get /48 or /32 block for each of your own AS
Traffic Engineering
• Load balancing
Route / Prefix Aggregation
NOT a good practice
– Use BGP community instead
customers to announce to other networks the
portable addresses that you assign to them
Route Leakage
• Do NOT distribute (leak) to your peers (directly via BLPA or indirectly via MLPA) the routes which do not belong to yourself and your transit customers
• It will waste your bandwidth serving those which do not pay you
• May also affect the overall performance and people may not appreciate you at all
• You should do this ONLY to your transit customers (as part of full routes provisioning)
peering connections
• Almost all IXPs support dual-stack
– If they do not, you should disconnect
Transparency of Ethernet Local Loops
• Metro Ethernet services provided by some local loop providers in HK may not be transparent enough
– May observe some unrelated traffic
– May cause problems to your IXP connection
– May not support LACP
– GE is usually worse
– 10GE is usually better (but not 100%)
– Trial or guarantee is a must before you pay for them
• Same applies to IEPL
• Make sure your routers support 4-byte ASNs
• Do monitor the growth of number of routes learnt from your peers (or MLPA route servers) and adjust your max prefix settings accordingly
• Do monitor the utilization of your links closely and do upgrade before they are full
• Set up your own route / route6 / as-set objects on IRRDB and keep them up-to-date – APNIC RRDB is free if you are an APNIC member
– Do not let your upstream providers to do it for you • They will mess things up
Thank You!

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